Host 'xxx.xx.xx-xx.xx.com' is not allowed to connect to this MySQL serverConnection closed by foreig

线上新建一个db，远程telnet xx 3306报错如下：

[xxx@xxx cacti]$ telnet db01.xx.com 3306
Trying xx.xx.xx.1...
Connected to db01.xx.com.
Escape character is '^]'.
YHost 'db01.xx.com' is not allowed to connect to this MySQL serverConnection closed by foreign host.

网上查了很多资料，说是执行如下：

 mysql>UPDATE mysql.user SET Host='%' WHERE Host='localhost';
    mysql>GRANT ALL PRIVILEGES ON *.* TO root@"%" ;
    mysql>FLUSH PRIVILEGES;

就可以搞定。不过我对此有怀疑，root设置成%多危险啊，虽然这个可以成功，但是隐患不少。

自己研究了下，发现了原因：

当新的db，必须至少有一个远程的mysql帐号存在，才能允许telnet xx 3306成功。

所以只要建立一个非localhost或者127.0.0.1的mysql帐号，那么肯定能执行telnet xx 3306成功。此问题关键信息在：by foreign host